Microsoft's Xbox system doesn't violate patents owned by Google 's Motorola Mobility unit, a U.S. trade judge said. The U.S. International Trade Commission Judge David Shaw on Friday sided with Microsoft in the case. His findings are subject to review by the Commission, which is able to block imports of products that infringe U.S. patents.

Motorola Mobility accused Microsoft of infringing five patents when it filed its complaint in 2010. Four have been dropped. The reamining patent allows devices to communicate wirelessly over short distances.

Motorola filed the ITC complaint in November 2010, in retaliation for Microsoft?s demands for royalties on phones using Google?s Android operating system.

In April 2012, ITC Judge David Shaw said in a preliminary decision that Microsoft infringed four patents and did not infringe on a fifth. The commission ordered him to revisit the case.

Motorola Mobility dropped the two video-decoding patents after Google reached an agreement with the U.S. Federal Trade Commission in January regarding how it deals with patents that relate to standard essential standards. The other two that were dropped expire this year.

The case is at the International Trade Commission, No. 337-752.